WO2024048586A1 - Ensemble électrode à membrane pour réservoir d'électrolyse de l'eau - Google Patents

Ensemble électrode à membrane pour réservoir d'électrolyse de l'eau Download PDF

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Publication number
WO2024048586A1
WO2024048586A1 PCT/JP2023/031242 JP2023031242W WO2024048586A1 WO 2024048586 A1 WO2024048586 A1 WO 2024048586A1 JP 2023031242 W JP2023031242 W JP 2023031242W WO 2024048586 A1 WO2024048586 A1 WO 2024048586A1
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catalyst layer
polymer electrolyte
electrolyte membrane
film
main surface
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PCT/JP2023/031242
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English (en)
Japanese (ja)
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博之 茅根
弘幸 盛岡
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Ｔｏｐｐａｎホールディングス株式会社
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Publication of WO2024048586A1 publication Critical patent/WO2024048586A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/02—Hydrogen or oxygen
    • C25B1/04—Hydrogen or oxygen by electrolysis of water
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B13/00—Diaphragms; Spacing elements
    • C25B13/04—Diaphragms; Spacing elements characterised by the material
    • C25B13/08—Diaphragms; Spacing elements characterised by the material based on organic materials
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
    • C25B9/17—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof
    • C25B9/19—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms
    • C25B9/23—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof with diaphragms comprising ion-exchange membranes in or on which electrode material is embedded

Definitions

  • the present invention relates to a membrane electrode assembly for a water electrolyzer.
  • a typical configuration of a solid polymer water electrolysis device is a membrane electrode assembly (Fig. 2) in which electrode catalyst layers are arranged on both sides of a proton-conducting polymer electrolyte membrane, and a current collector and terminals on the outside. It has a plate (see Patent Document 1).
  • the peripheral area of the polymer electrolyte membrane that is not covered by the electrode catalyst layer is used as part of the gasket in order to improve the sealing performance of the liquid. is possible.
  • the polymer electrolyte membrane is an expensive material, and the peripheral area of the polymer electrolyte membrane that is not covered with the electrode catalyst layer is an area that does not contribute to reactions such as electrolysis in the first place.
  • a configuration in which the electrolyte membrane is part of the gasket is not necessarily an appropriate structure.
  • the present invention has been made in view of the above problems, and aims to provide a membrane electrode assembly for a water electrolyzer that can reduce the amount of polymer electrolyte membrane used while maintaining liquid sealing properties.
  • a polymer electrolyte membrane having a first main surface and a second main surface, a first electrode catalyst layer provided on the first main surface of the polymer electrolyte membrane; a second electrode catalyst layer provided on the second main surface of the polymer electrolyte membrane; an annular peripheral film disposed so as to surround the peripheral surface of the polymer electrolyte membrane;
  • a first adhesive film having a base material layer and an adhesive layer, The first main surface of the polymer electrolyte membrane has a first annular uncovered portion that is not covered by the first electrode catalyst layer along the outer periphery of the first main surface, The adhesive layer of the first adhesive film covers the first annular uncoated portion of the polymer electrolyte membrane and the main surface of the peripheral film on the same side as the first main surface of the polymer electrolyte membrane.
  • a membrane electrode assembly for a water electrolyzer which is attached to a membrane electrode assembly for a water electrolyzer.
  • the outer peripheral film when assembled in the water electrolyzer, the outer peripheral film can function as a part of the gasket structure that prevents liquid from leaking to the outside between the pair of separators. Therefore, compared to the conventional gasket structure, the amount of polymer electrolyte material used in the gasket structure can be suppressed while maintaining liquid sealing properties. Furthermore, since the outer peripheral film and the annular non-coated portion are fixed with the adhesive film, handling of the membrane electrode assembly is improved when the membrane electrode assembly is assembled into a water electrolytic cell.
  • [2] Further comprising a second adhesive film having a base layer and an adhesive layer,
  • the second main surface of the polymer electrolyte membrane has a second annular uncovered portion that is not covered by the second electrode catalyst layer along the outer periphery of the second main surface,
  • the adhesive layer of the second adhesive film covers the second annular uncoated portion of the polymer electrolyte membrane and the main surface of the peripheral film on the same side as the second main surface of the polymer electrolyte membrane.
  • the difference in level between the outer peripheral film and the polymer electrolyte membrane can be reduced, so that the outer peripheral film and the polymer electrolyte membrane can be fixed with higher adhesion using the adhesive film.
  • a water electrolyzer comprising the membrane electrode assembly for a water electrolyzer according to any one of [1] to [4].
  • a membrane electrode assembly for a water electrolyzer can be obtained in which the amount of polymer electrolyte membrane used is small.
  • FIG. 1 is a schematic cross-sectional view of the structure of a membrane electrode assembly for a water electrolyzer in one embodiment. It is a cross-sectional schematic diagram of the cathode catalyst layer of the membrane electrode assembly for water electrolyzers in one embodiment. It is a cross-sectional schematic diagram of the reading electrode catalyst layer of the membrane electrode assembly for water electrolyzers in one embodiment.
  • FIG. 2 is a schematic cross-sectional view of a water electrolyzer in one embodiment.
  • FIG. 1 is a cross-sectional view schematically showing a configuration example of a membrane electrode assembly 6 according to an embodiment of the present invention.
  • the membrane electrode assembly 6 includes a polymer electrolyte membrane 1, an anode catalyst layer 2 (first electrode catalyst layer) provided on a first main surface 1A and a second main surface 1B of the polymer electrolyte membrane 1, respectively. It includes a cathode catalyst layer 3 (second electrode catalyst layer), an outer peripheral film 4, an adhesive film (first adhesive film) 5A, and an adhesive film (second adhesive film) 5B.
  • the outer shape of the anode catalyst layer 2 and the outer shape of the cathode catalyst layer 3 are almost the same, and the outer shape of the polymer electrolyte membrane 1 is the same as that of the anode catalyst layer 3. 2 and the cathode catalyst layer 3.
  • the outer shape of the polymer electrolyte membrane 1 and the outer shapes of the anode catalyst layer 2 and the cathode catalyst layer are not particularly limited, and may be rectangular (including square), for example.
  • the external dimensions of the polymer electrolyte membrane 1 are larger than those of the anode catalyst layer 2 and the cathode catalyst layer.
  • the external dimensions of the polymer electrolyte membrane 1 when the shape of the polymer electrolyte membrane 1 is rectangular are as follows: It is desirable that each of the vertical and horizontal directions is 1.05 to 1.25 times larger than the external dimensions when the shape is rectangular, and should be adjusted according to the usage environment in the water electrolyzer. be able to.
  • the size of the anode catalyst layer 2 and the cathode catalyst layer 3 is smaller than the external shape of the polymer electrolyte membrane 1. Therefore, along the outer periphery of the polymer electrolyte membrane 1 on each of the first main surface 1A on the anode catalyst layer 2 side and the second main surface 1B on the cathode catalyst layer 3 side of the polymer electrolyte membrane 1, Annular uncovered portions 1AN and 1BN that are not covered by the anode catalyst layer 2 or the cathode catalyst layer 3 are formed.
  • the width NW of the annular uncovered portions 1AN and 1BN can be 10 to 100 mm.
  • the polymer electrolyte membrane 1 is made of a polymer material having proton conductivity, and for example, a fluorine-based electrolyte membrane or a hydrocarbon-based polymer electrolyte membrane can be used.
  • a fluorine-based electrolyte membrane or a hydrocarbon-based polymer electrolyte membrane can be used.
  • the fluoropolymer electrolyte membrane include Nafion (registered trademark) manufactured by DuPont, Flemion (registered trademark) manufactured by Asahi Glass Co., Ltd., Aciplex (registered trademark) manufactured by Asahi Kasei Corporation, and Gore Select (registered trademark) manufactured by Gore. etc. can be used.
  • hydrocarbon polymer electrolyte membrane for example, electrolyte membranes such as sulfonated polyetherketone, sulfonated polyethersulfone, sulfonated polyetherethersulfone, sulfonated polysulfide, and sulfonated polyphenylene can be used.
  • the thickness of the polymer electrolyte membrane 1 can be, for example, 0.05 to 0.25 mm.
  • FIG. 2 is a cathode cross-sectional view schematically showing the structure of the cathode catalyst layer 3 of this embodiment.
  • Cathode catalyst layer 3 includes cathode catalyst particles 7 , polymer electrolyte 9 , and fibrous material 10 .
  • the cathode catalyst particles 7 are cathode catalyst particles for carrying out a reduction reaction using protons in the catholyte.
  • Cathode catalyst particles 7 platinum group elements, metals, alloys, oxides, and double oxides of these metals can be used.
  • platinum group elements include platinum, palladium, ruthenium, iridium, rhodium, and osmium
  • metals include iron, lead, copper, chromium, cobalt, nickel, manganese, vanadium, molybdenum, gallium, and aluminum.
  • double oxide herein refers to an oxide consisting of two types of metals.
  • the cathode catalyst particles 7 are made of one or more metals selected from platinum, gold, palladium, rhodium, ruthenium, and iridium, they have excellent electrode reactivity and perform electrode reactions efficiently and stably. be able to. It is preferable that the cathode catalyst particles 7 are made of one or more metals selected from platinum, gold, palladium, rhodium, ruthenium, and iridium because they exhibit high activity.
  • the above-mentioned catalyst is generally supported on an electron-conductive catalyst carrier 8.
  • carbon particles are generally used.
  • the type of carbon particles is not limited as long as they are fine particles, have conductivity, and are not affected by the catalyst.
  • carbon particles for example, carbon black, graphite, graphite, activated carbon, carbon fiber, carbon nanotube, and fullerene can be used.
  • the average particle diameter of the carbon particles is preferably contained within a range of 10 nm or more and 1000 nm or less, and more preferably contained within a range of 10 nm or more and 100 nm or less.
  • the average particle diameter is the average particle diameter determined from a SEM image.
  • the average particle diameter of the carbon particles is within the range of 10 nm or more and 1000 nm or less because the activity and stability of the catalyst are improved. Further, it is preferable that the average particle diameter of the carbon particles is within the range of 10 nm or more and 1000 nm or less, because electron conduction paths are likely to be formed.
  • FIG. 3 is a cross-sectional view schematically showing the structure of the anode catalyst layer 2 of this embodiment.
  • the anode catalyst layer 2 includes anode catalyst particles 12 and a polymer electrolyte 9. Further, the anode catalyst layer 2 may include the fibrous material 10.
  • the anode catalyst particles 12 are anode catalyst particles for carrying out an oxidation reaction in the anolyte.
  • anode catalyst particles 12 As the anode catalyst particles 12 included in the anode catalyst layer, for example, metals included in the platinum group, metals other than the platinum group, or alloys, oxides, sub-oxides, and carbides thereof can be used. Among these, ruthenium, rhodium, palladium, iridium, platinum, and alloys containing at least one of these have high catalytic activity and are suitable. In addition, the catalyst particles may be only one type of the above examples, or may be a combination of two or more types.
  • the polymer electrolyte 9 only needs to have proton conductivity, and the same material as the polymer electrolyte membrane 1 can also be used.
  • a fluorine-based polymer electrolyte or a hydrocarbon-based polymer electrolyte can be used.
  • fluorine-based polymer electrolyte for example, Nafion (registered trademark) material manufactured by DuPont, etc. can be used.
  • hydrocarbon polymer electrolyte for example, electrolytes such as sulfonated polyether ketone, sulfonated polyether sulfone, sulfonated polyether ether sulfone, sulfonated polysulfide, and sulfonated polyphenylene can be used.
  • carbon fiber or polymer fiber can be used as the fibrous material 10 used in the cathode catalyst layer.
  • carbon fibers include carbon fibers, carbon nanotubes, carbon nanohorns, and the like.
  • carbon nanofibers or carbon nanotubes are suitable in terms of conductivity and dispersibility.
  • the amount of carbon fiber blended is preferably within a range of 0.3 to 1.5 times the mass of the carrier in the catalyst-supported particles. If the carbon fiber content is within the above numerical range, pores 11 of a suitable size can be formed in a suitable amount in the cathode catalyst layer.
  • the average fiber diameter of the carbon fiber is preferably 300 nm or less, more preferably 200 nm or less.
  • the average fiber diameter of the carbon fibers is 300 nm or less, appropriate fineness is ensured as a fiber material to be included in the cathode catalyst layer. Further, if the average fiber diameter of the carbon fibers is 50 nm or more, an appropriate thickness is ensured, the strength of the cathode catalyst layer is increased, and the effect of suppressing the occurrence of cracks is obtained.
  • the average fiber length of the carbon fiber is preferably within the range of 1.0 ⁇ m or more and 20 ⁇ m or less. If the average fiber length of the carbon fibers is within the above numerical range, pores 11 of a suitable size can be formed in the cathode catalyst layer.
  • the fibrous material 10 is a polymer fiber
  • an ionomer-adsorbing fiber, a conductive polymer nanofiber, or a proton-conducting fiber, which has the property of adsorbing a polymer electrolyte is used as the polymer fiber.
  • the amount of ionomer adsorbed by the ionomer-adsorbing fiber is 10 mg or more per 1 g of the ionomer-adsorbing fiber, and for example, a polymer fiber having at least one cation exchange group is used.
  • Proton conductivity can be improved by using proton conductive fibers.
  • the proton-conducting fiber may be any polymeric fiber obtained by processing an ionomer having proton conductivity into a fibrous form.
  • a fluorine-based polymer electrolyte, a hydrocarbon-based polymer electrolyte, or the like can be used as a material for forming the proton-conducting fiber.
  • polymer fibers having cation exchange groups such as hydroxyl groups, carbonyl groups, sulfonic acid groups, phosphorous acid groups, and amino groups added to the terminal groups of the polymer structure can be used.
  • the amount of ionomer adsorbed on the ionomer-adsorbing fibers can be determined by contacting the ionomer-adsorbing fibers with a dispersion containing a predetermined concentration of ionomer, filtering through a predetermined filter (for example, diameter 0.3 to 0.5 ⁇ m), and The concentration of the ionomer contained in the liquid can be measured and calculated. Furthermore, proton conductivity can be improved by using proton conductive fibers.
  • the blending amount of the polymer fiber is preferably within the range of 0.05 times or more and 0.3 times or less of the mass of the carrier in the catalyst-supported particles. If the polymer fiber content is within the above numerical range, pores 11 of a suitable size can be formed in a suitable amount in the cathode catalyst layer.
  • the average fiber diameter of the polymer fiber is preferably 500 nm or less, more preferably 400 nm or less.
  • the average fiber diameter of the polymer fibers is 500 nm or less, appropriate fineness is ensured as a fiber material to be included in the cathode catalyst layer. Further, if the average fiber diameter of the polymer fibers is 100 nm or more, an appropriate thickness is ensured, the strength of the cathode catalyst layer is increased, and the effect of suppressing crack generation is obtained.
  • the average fiber length of the polymer fiber is preferably within the range of 1.0 ⁇ m or more and 40 ⁇ m or less. If the average fiber length of the polymer fibers is within the above numerical range, pores 11 of a suitable size can be formed in the cathode catalyst layer.
  • these fibrous substances may be used alone, or two or more types may be used in combination, and conductive fibers and polymer fibers may be used in combination.
  • ionomer-adsorbing fibers As the fibrous material 13 used in the anode catalyst layer, ionomer-adsorbing fibers, conductive polymer nanofibers, or proton-conducting fibers having the property of adsorbing polymer electrolytes are used.
  • the same material as the polymer fiber used in the cathode catalyst layer can also be used.
  • the blending amount of the fibrous material 13 is preferably within a range of 0.005 times or more and 0.2 times or less of the mass of the catalyst particles. If the content of the fibrous material 13 is within the above numerical range, pores 11 of a suitable size can be formed in a suitable amount in the anode catalyst layer.
  • the average fiber diameter of the fibrous material 13 is preferably 500 nm or less, more preferably 400 nm or less.
  • the average fiber diameter of the polymer fiber is 500 nm or less, a suitable fineness is ensured as a fiber material to be included in the anode catalyst layer.
  • the average fiber diameter of the polymer fibers is 100 nm or more, an appropriate thickness is ensured, the strength of the anode catalyst layer is increased, and the effect of suppressing the occurrence of cracks is obtained.
  • the average fiber length of the fibrous material 13 is preferably within the range of 1.0 ⁇ m or more and 40 ⁇ m or less. If the average fiber length of the polymer fibers is within the above numerical range, pores 11 of a suitable size can be formed in the anode catalyst layer.
  • the outer peripheral film 4 is arranged so as to surround the outer peripheral surface 1G of the polymer electrolyte membrane 1, and has an annular shape.
  • the outer peripheral film 4 has an opening 4P corresponding to the external shape of the polymer electrolyte membrane 1, and the polymer electrolyte membrane 1 is accommodated in the opening 4P of the outer peripheral film 4.
  • the outer shape of the opening 4P of the outer peripheral film 4 may be, for example, a shape corresponding to the outer shape of the polymer electrolyte membrane 1, such as a rectangle (including a square).
  • the external shape of the peripheral film 4 is also not particularly limited, and may be rectangular (including square) or the like.
  • the distance between the opening 4P of the outer peripheral film 4 and the outer peripheral surface 1G of the polymer electrolyte membrane 1 is preferably 20 mm or less.
  • the width 4W in the radial direction of the ring of the outer peripheral film 4 is not particularly limited, but may be, for example, 100 to 300 mm.
  • the thickness of the outer peripheral film 4 is preferably within ⁇ 10% of the thickness of the polymer electrolyte membrane 1. This reduces the level difference between the main surfaces of the peripheral film 4 and the polymer electrolyte membrane 1, resulting in excellent liquid sealing properties when the membrane electrode assembly 6 is sandwiched between gaskets or separators, which will be described later. .
  • the outer peripheral film 4 for example, a resin film is used.
  • resins are polyethylene terephthalate, polyurethane.
  • the material of the outer peripheral film 4 does not contain a polymer electrolyte.
  • the outer peripheral film 4 is made of polyurethane, it easily follows the swelling and deformation of the polymer electrolyte membrane.
  • the outer peripheral film is made of polyethylene terephthalate, it has excellent strength.
  • Adhesive films 5A and 5B each have a base layer 51 and an adhesive layer 52.
  • An example of the base layer 51 is a resin film such as polyethylene terephthalate or polyurethane.
  • the thickness of the base material layer 51 can be 25 to 100 ⁇ m.
  • the base material layer 51 is made of polyurethane, it easily follows the swelling and deformation of the polymer electrolyte membrane.
  • the base material layer 51 is made of polyethylene terephthalate, it has excellent strength.
  • Examples of the adhesive layer 52 are an acrylic adhesive layer, a urethane adhesive layer, and a rubber adhesive layer.
  • the thickness of the adhesive layer 52 can be 5 to 25 ⁇ m.
  • the adhesive layer 52 of the adhesive film 5A is attached to the annular uncoated portion 1AN of the polymer electrolyte membrane 1 and to the main surface 4A of the outer peripheral film 4 on the same side as the first main surface 1A of the polymer electrolyte membrane 1. It is pasted.
  • the adhesive layer 52 of the adhesive film 5B is attached to the annular uncoated portion 1BN of the polymer electrolyte membrane 1 and to the main surface 4B of the outer peripheral film 4 on the same side as the second main surface 1B of the polymer electrolyte membrane 1. It is pasted.
  • the adhesive films 5A and 5B are pasted over the annular uncoated portions 1AN and 1BN of the polymer electrolyte and the main surface of the outer peripheral film 4, the polymer electrolyte membrane 1 and the outer peripheral film 4 are fixed.
  • the thickness of the adhesive films 5A and 5B is not particularly limited, but is preferably 30 to 125 ⁇ m.
  • the thickness of the adhesive films 5A and 5B is preferably smaller than the respective thicknesses of the cathode catalyst layer 3 and the anode catalyst layer 2.
  • the peel strength of the adhesive films 5A and 5B is 0.3 N/25 mm or more with respect to the polyimide film. In this case, when manufacturing the membrane electrode assembly 6 (when applying ink to the electrode catalyst layer), when assembling a water electrolyzer using the membrane electrode assembly, or when using the water electrolyzer, the adhesive films 5A and 5B are Peeling can be suppressed.
  • the adhesive films 5A and 5B have an annular shape when viewed from the thickness direction.
  • the adhesive films 5A and 5B can have an annular shape with an opening 5D in the center. It is preferable that the adhesive films 5A and 5B have an annular shape with an opening 5D having the same shape as or a larger diameter than the anode catalyst layer 2 and the cathode catalyst layer 3.
  • the outer shape of the adhesive films 5A, 5B can be a rectangle (including a square) that is equivalent to the outer shape of the outer peripheral film 4. It is preferable that the openings 5D of the adhesive films 5A and 5B do not contact the anode catalyst layer 2 and the cathode catalyst layer 3 when they are attached to the polymer electrolyte membrane 1.
  • the adhesive films 5A and 5B may cover at least a portion of each main surface of the outer peripheral film 4, but preferably cover the entire main surface of the outer peripheral film 4.
  • the anode catalyst layer 2 and the cathode catalyst layer 3 of this embodiment can be manufactured by preparing an electrode catalyst layer slurry, coating it on a base material, etc., and drying it.
  • a catalyst ink is prepared by mixing each component constituting the electrode catalyst layer, that is, a catalyst, a polymer electrolyte, and a fibrous material using a dispersion medium.
  • the solvent used as the catalyst ink dispersion medium is particularly limited as long as it does not corrode each component constituting the electrode catalyst layer and can dissolve the polymer electrolyte in a highly fluid state or disperse it as a fine gel. It's not a thing. However, it is desirable that the solvent contains at least a volatile organic solvent.
  • the solvent used as a dispersion medium for the catalyst ink may be water, alcohols, ketone solvents, ether solvents, polar solvents, and the like.
  • alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, acetone, methyl ethyl ketone, methyl butyl ketone, methyl Ketones such as isobutyl ketone, methyl amyl ketone, pentanone, heptanone, cyclohexanone, methyl cyclohexanone, acetonyl acetone, diethyl ketone, dipropyl ketone, diisobutyl ketone, tetrahydrofuran, dioxane, diethylene glycol dimethyl ether, anisole, methoxytoluene, dibutyl ether, etc.
  • alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol,
  • Ether solvents and polar solvents such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, ethylene glycol, diethylene glycol, diacetone alcohol, and 1-methoxy-2-propanol can be used as appropriate.
  • the solvent may be a mixed solvent in which two or more of the above-mentioned materials are mixed.
  • the dispersion medium may contain water that is compatible with the ionomer, that is, water that has a high affinity for the ionomer.
  • the amount of water added to the dispersion medium is not particularly limited as long as the ionomer does not separate and cause cloudiness or gelation.
  • a dispersant may be included in the catalyst ink in order to disperse the catalyst-supported carbon particles in the catalyst ink.
  • the catalyst ink may be subjected to a dispersion treatment if necessary.
  • the dispersion treatment is not particularly limited as long as it is a method that can disperse each component contained in the catalyst ink. Examples include treatment with a planetary ball mill and roll mill, treatment with a shear mill, treatment with a wet mill, ultrasonic dispersion treatment, and treatment with a homogenizer.
  • an electrode catalyst layer is formed by performing a drying process to volatilize the dispersion medium.
  • the base material used when forming the anode catalyst layer 2 and the cathode catalyst layer 3 for example, a transfer base material that is peeled off after transferring the anode catalyst layer 2 and the cathode catalyst layer 3 to the polymer electrolyte membrane 1 is used.
  • a transfer base material for example, a resin film is used.
  • the polymer electrolyte membrane 1 may be used as a base material used when forming the anode catalyst layer 2 and the cathode catalyst layer 3.
  • Examples of the method for applying the slurry for the electrode catalyst layer onto the substrate include, but are not particularly limited to, a doctor blade method, a die coating method, a dipping method, a screen printing method, a laminator roll coating method, a spray method, and the like.
  • Examples of methods for drying the electrode catalyst layer slurry applied to the base material include hot air drying and IR drying.
  • the drying temperature of the slurry for electrode catalyst layer may be within the range of 40°C or higher and 200°C or lower, preferably within the range of 40°C or higher and 120°C or lower.
  • the drying time of the slurry for the electrode catalyst layer may be from 0.5 minutes to 1 hour, preferably from 1 minute to 30 minutes.
  • the manufacturing method uses the polymer electrolyte membrane 1 as a base material for forming the anode catalyst layer 2 and the cathode catalyst layer 3, the anode catalyst layer 2 and the cathode catalyst layer 3 are formed on the surface of the polymer electrolyte membrane 1. formed directly in Therefore, the adhesion between the polymer electrolyte membrane 1 and the anode catalyst layer 2 and the cathode catalyst layer 3 is increased, and since pressurization for joining the anode catalyst layer 2 and the cathode catalyst layer 3 is not required, the anode catalyst The collapse of the layer 2 and the cathode catalyst layer 3 (the collapse of the pores 11) is also suppressed. Therefore, it is preferable to use the polymer electrolyte membrane 1 as the base material for forming the anode catalyst layer 2 and the cathode catalyst layer 3.
  • the polymer electrolyte membrane 1 since the polymer electrolyte membrane 1 generally has a characteristic of having a large degree of swelling and shrinkage, when the polymer electrolyte membrane 1 is used as a base material, compared to when a transfer base material is used as a base material. Therefore, the volume change of the base material during the drying process of the coating film that will become the anode catalyst layer 2 and the cathode catalyst layer 3 is large. Therefore, if the electrode catalyst layer does not contain a fibrous substance, cracks are likely to occur in the electrode catalyst layer.
  • the electrode catalyst layer contains a fibrous substance, even if the volume of the polymer electrolyte membrane 1, which is the base material, changes significantly during the manufacturing process of the anode catalyst layer 2 and the cathode catalyst layer 3, Since the occurrence of cracks is suppressed by containing the fibrous material, a manufacturing method using the polymer electrolyte membrane 1 as a base material for forming the anode catalyst layer 2 and the cathode catalyst layer 3 can be used.
  • the size of the anode catalyst layer 2 and the cathode catalyst layer 3 is smaller than the external shape of the polymer electrolyte membrane 1. Therefore, on each of the first main surface 1A on the anode catalyst layer 2 side of the polymer electrolyte membrane 1 and the second main surface 1B on the cathode catalyst layer 3 side, the anode Annular uncovered portions 1AN and 1BN that are not covered by the catalyst layer 2 and the cathode catalyst layer 3 are formed.
  • the membrane electrode assembly 6 is prepared by affixing the adhesive films 5A and 5B over the annular uncoated portions 1AN and 1BN of the polymer electrolyte membrane 1 and the respective main surfaces 4A and 4B of the outer peripheral film 4. . Note that there is no problem even if the polymer electrolyte membrane 1 and the outer peripheral film 4 are bonded together using adhesive films 5A and 5B before forming the anode catalyst layer 2 and the cathode catalyst layer 3.
  • a resin film is used as the outer peripheral film 4 and the adhesive films 5A and 5B.
  • the adhesive films 5A and 5B are cut out and opened so as to have the same shape or larger outer shape as the anode catalyst layer 2 and the cathode catalyst layer 3, so that they do not come into contact with the anode catalyst layer 2 and the cathode catalyst layer 3. .
  • the adhesive films 5A and 5B are attached so as not to contact the anode catalyst layer 2 and the cathode catalyst layer 3 formed on the polymer electrolyte membrane 1. Therefore, the outer dimensions of the polymer electrolyte membrane 1 are larger than those of the anode catalyst layer 2 and the cathode catalyst layer 3.
  • the external dimensions of the polymer electrolyte membrane 1 when the shape is rectangular are those of the anode catalyst layer 2 and the cathode catalyst layer 3. It is desirable that each of the vertical and horizontal directions is 1.05 to 1.25 times larger than the external dimensions in the case where the electrolytic cell is used, and is adjusted according to the environment in which the water electrolyzer is used.
  • the order in which the anode catalyst layer 2 and cathode catalyst layer 3 are formed does not matter, but in the step of forming the electrode catalyst layer first, it is recommended to attach a resin film such as PET to the area where the electrode catalyst layer will be formed later. preferable. This can be expected to have the effect of suppressing swelling and deformation of the polymer electrolyte membrane due to catalyst ink dripping.
  • the adhesive film is attached to both the first principal surface 1A and the second principal surface 1B, but the present invention may be implemented even if the adhesive film is attached to only one of the surfaces. is possible.
  • the water electrolyzer 100 includes the above membrane electrode assembly 6, a gas diffusion layer 22A on the anode side (oxygen generation anode side), a gas diffusion layer 22C on the cathode side (hydrogen generation cathode side), a pair of annular gaskets 23A, 23C, It also includes a pair of separators 26A and 26C.
  • the gas diffusion layer 22A on the anode side is arranged on the anode catalyst layer 2.
  • the gas diffusion layer 22A on the anode side may be made of a conductive porous material such as a Ti sintered plate.
  • the gas diffusion layer 22C on the cathode side is arranged on the cathode catalyst layer 3.
  • the gas diffusion layer 22C on the cathode side may be made of a conductive porous material such as carbon paper.
  • the separator 26A is provided above the gas diffusion layer 22A on the anode side, and the separator 26C is provided below the gas diffusion layer 22C on the cathode side.
  • the separators 26A and 26C have grooves (not shown) on their main surfaces (both main surfaces) that allow fluids such as generated gas, steam gas, and cooling water to flow.
  • the material of the separators 26A, 26C is preferably a conductor such as a metal material, and is impermeable to gas and liquid.
  • the external shapes of the separators 26A and 26C correspond to the external shape of the outer peripheral film 4 (for example, rectangular, etc.). Therefore, annular gaskets 23A and 23C are provided between the adhesive film 5A and the separator 26A, and between the adhesive film 5B and the separator 26C, respectively.
  • the annular gasket 23A has an opening in the center and can accommodate the anode catalyst layer 2 and the anode side gas diffusion layer 22A, and the annular gasket 23A can accommodate the cathode catalyst layer 3 and the cathode side gas diffusion layer 22C. Do not overlap.
  • the annular gasket 23C has an opening in the center and can accommodate the cathode catalyst layer 3 and the cathode side gas diffusion layer 22C. Do not overlap. Therefore, the annular gaskets 23A, 23C can perform the function of preventing leakage of liquid such as water.
  • the material of the annular gaskets 23A and 23C can be, for example, EPDM (ethylene propylene diene rubber).
  • the thickness of the annular gasket 23A is within a range such that the ratio of the total thickness of the adhesive film 5A and the annular gasket 23A to the total thickness of the anode catalyst layer 2 and the anode side gas diffusion layer 22A is 0.9 to 1.1. It can be set as appropriate. This ratio may be between 0.95 and 1.05.
  • the thickness of the annular gasket 23C is such that the ratio of the total thickness of the adhesive film 5B and the annular gasket 23C to the total thickness of the cathode catalyst layer 3 and the gas diffusion layer 22C on the cathode side is 0.9 to 1.1. It can be set as appropriate. This ratio may be between 0.95 and 1.05.
  • the water electrolyzer 100 is an example of a single cell, it may have a cell stack structure in which a plurality of single cells are stacked.
  • the polymer electrolyte membrane 1, the anode catalyst layer 2, the gas diffusion layer 22A on the anode side, the cathode catalyst layer 3, and the gas diffusion layer 22C on the cathode side have a separator 26A, a separator 26C, and a gasket structure. It is housed in a space V formed by the body GK, and is sealed by a gasket structure GK to prevent liquid from leaking from the space V to the outside.
  • the gasket structure GK is a laminate including an annular gasket 23C, an adhesive film 5B, an outer peripheral film 4, an adhesive film 5A, and an annular gasket 23A.
  • water is supplied to the anode catalyst layer 2 and the cathode catalyst layer 3 through the gas flow path of the separator 26A and the gas diffusion layer 22A on the anode side, and is further supplied to the anode catalyst layer 2 and the cathode catalyst layer 3.
  • oxygen gas is generated from water in the anode catalyst layer 2
  • hydrogen gas is generated from water in the cathode catalyst layer 3
  • the obtained gas is transferred to the gas in the separators 26A and 26C.
  • the water is separated and taken out of the water electrolyzer 100 through a flow path.
  • the outer peripheral film 4 when assembled in the water electrolyzer 100, the outer peripheral film 4 forms a gasket structure that prevents liquid leakage between the separators 26A and 26C. Can function as part of GK. Therefore, the amount of polymer electrolyte material used in the gasket structure GK can be suppressed compared to the conventional case. Furthermore, as shown in FIG. 1, since the outer peripheral film 4 and the annular uncoated parts 1AN and 1BN are fixed with the adhesive films 5A and 5B, when the membrane electrode assembly 6 is assembled into the water electrolytic cell 100, etc. The handling properties of the membrane electrode assembly 6 are improved.
  • an annular PET film with a thickness of 188 ⁇ m as the outer peripheral film 4 was placed so as to surround the outer periphery of the Nafion (registered trademark) membrane (thickness: 180 to 200 ⁇ m) as the polymer electrolyte membrane 1.
  • a circular adhesive PET film with a thickness of 25 ⁇ m has openings of the same size as the external shapes of the anode catalyst layer 2 and the cathode catalyst layer, and has an external shape of the same size as the external shape of the outer peripheral film 4. was bonded to the first main surface 1A of the polymer electrolyte membrane 1 and the main surface 4A of the outer peripheral film 4 on the same side as the first main surface 1A.
  • the same annular adhesive PET film is bonded to the second main surface 1B of the polymer electrolyte membrane 1 and the main surface 4B of the outer peripheral film 4 on the same side as the second main surface 1B, and coated.
  • the construction base material was prepared.
  • the external shape of the Nafion (registered trademark) membrane was prepared to be 1.1 times larger in both the vertical and horizontal directions than the external shapes of the anode and cathode catalyst layers.
  • Each annular adhesive PET film was bonded to the annular uncoated portion 1AN or 1BN of the Nafion (registered trademark) membrane over the main surface 4A or 4B of the outer peripheral film 4.
  • the bonding conditions were a temperature of 23 ⁇ 2° C., a pressure of 0.1 MPa, and a speed of 2 m/min.
  • the peel strength of the adhesive PET film was determined by measuring the 180 degree peel force under the conditions of JIS Z 0237 at a temperature of 23 ⁇ 2 °C and a relative humidity of 65 ⁇ 5% RH. It was 35N/25mm.
  • PtRu/C catalyst TEC61E54 manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.
  • Nafion registered trademark
  • dispersion liquid manufactured by Wako Pure Chemical Industries, Ltd.
  • carbon as a fibrous material.
  • a catalyst ink was prepared by adding fibers and using an appropriate solvent. The amount of fibrous material blended was set to be 1.0 times the mass of the carrier in the catalyst-supporting particles. It was confirmed that the average fiber diameter of the carbon fibers was 150 nm.
  • the obtained slurry for a cathode catalyst layer was coated on one surface of the prepared base material by a die coating method so that the total supported amount of Pt and Ru was 0.5 mg/cm 2 per electrode area. Thereafter, by drying in an oven at 80° C., a laminate in which a cathode catalyst layer was formed on one side of the polymer electrolyte membrane was obtained.
  • a Nafion (trademark registered) dispersion liquid manufactured by Wako Pure Chemical Industries, Ltd.
  • a polymer electrolyte and polymer fibers as a fibrous substance were added to the iridium oxide powder, and a solvent was added as appropriate.
  • a catalyst ink was prepared using this method.
  • the blending amount of the fibrous material was set to be 0.01 times the mass of the anode catalyst layer. It was confirmed that the average fiber diameter of the fibrous material was 400 nm.
  • the obtained slurry for the anode catalyst layer was die-coated on the surface of the prepared base material on which the PtRu catalyst layer was not formed, so that the total amount of iridium oxide supported was 1.0 mg/cm 2 per electrode area. Coated by method. Thereafter, a membrane electrode assembly for a water electrolyzer was obtained by drying in an oven at 80°C.
  • Example 2 A membrane electrode assembly for a water electrolytic cell was obtained in the same manner as in Example 1 except that an adhesive PET film having a peel strength of 0.10 N/25 mm with respect to a polyimide film was used.
  • Example 3 A membrane electrode assembly for a water electrolytic cell was obtained in the same manner as in Example 1 except that an adhesive PET film having a peel strength of 0.28 N/25 mm with respect to a polyimide film was used.
  • Example 4 The procedure was the same as in Example 1, except that a polyurethane film was used instead of a PET film as the outer peripheral film 4, and a polyurethane film instead of a PET film was used as the base layer 51 of the adhesive films 5A and 5B.
  • the peel strength of the adhesive film against the polyimide film was the same as in Example 1.
  • the present invention has high industrial utility value because it is possible to form a membrane electrode assembly using a small amount of polymer electrolyte membrane. It is extremely suitable for manufacturing membrane electrode assemblies for water electrolyzers.
  • SYMBOLS 1... Polymer electrolyte membrane, 1AN... Annular non-coated part (first annular non-coated part), 1BN... Annular non-coated part (second annular non-coated part), 2... Anode catalyst layer, 3... Cathode catalyst layer, 4 ... Peripheral film, 5A, 5B ... Adhesive film, 6 ... Membrane electrode assembly, 7 ... Cathode catalyst particles, 8 ... Catalyst carrier, 9 ... Polymer electrolyte, 10 ... Fibrous material for cathode, 11 ... Holes, 12 ...Anode catalyst particles, 13...Fibrous material for anode, 100...Water electrolyzer.

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Abstract

Un ensemble électrode à membrane 6 pour un réservoir d'électrolyse de l'eau comprend : une membrane polyélectrolyte 1 comprenant une première surface primaire 1A et une seconde surface primaire 1B ; une première couche de catalyseur d'électrode 2 disposée sur la première surface primaire 1A de la membrane polyélectrolyte 1 ; une seconde couche de catalyseur d'électrode 3 disposée sur la seconde surface primaire 1B de la membrane polyélectrolyte 1 ; un film périphérique externe 4 qui a une forme annulaire et est disposé de façon à entourer la surface périphérique externe de la membrane polyélectrolyte 1 ; et un premier film adhésif 5A comprenant une couche de matériau de base 51 et une couche adhésive 52. La première surface primaire 1A de la membrane polyélectrolyte 1 comprend une première section annulaire non recouverte 1AN non recouverte par la première couche de catalyseur d'électrode 2 le long de la périphérie externe de la première surface primaire, et la couche adhésive 52 du premier film adhésif 5A est collée à la première section annulaire non recouverte 1AN de la membrane polyélectrolyte 1 et est collée à une surface primaire 4A du film périphérique externe 4 du même côté que la première surface primaire 1A de la membrane polyélectrolyte 1.
PCT/JP2023/031242 2022-08-30 2023-08-29 Ensemble électrode à membrane pour réservoir d'électrolyse de l'eau WO2024048586A1 (fr)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN2852407Y (zh) * 2005-11-17 2006-12-27 上海空间电源研究所 质子交换膜燃料电池的膜电极边框结构
JP2007042348A (ja) * 2005-08-02 2007-02-15 Nissan Motor Co Ltd 膜電極接合体及びその製造方法
JP2007095669A (ja) * 2005-08-31 2007-04-12 Nissan Motor Co Ltd 電解質膜−電極接合体
JP2014235962A (ja) * 2013-06-05 2014-12-15 凸版印刷株式会社 膜電極構造体及びその製造方法
KR20180071618A (ko) * 2016-12-20 2018-06-28 현대자동차주식회사 연료전지용 막전극 접합체 및 그 제조방법
WO2021132138A1 (fr) * 2019-12-23 2021-07-01 東レ株式会社 Procédé et appareil de production d'un ensemble membrane-électrode

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007042348A (ja) * 2005-08-02 2007-02-15 Nissan Motor Co Ltd 膜電極接合体及びその製造方法
JP2007095669A (ja) * 2005-08-31 2007-04-12 Nissan Motor Co Ltd 電解質膜−電極接合体
CN2852407Y (zh) * 2005-11-17 2006-12-27 上海空间电源研究所 质子交换膜燃料电池的膜电极边框结构
JP2014235962A (ja) * 2013-06-05 2014-12-15 凸版印刷株式会社 膜電極構造体及びその製造方法
KR20180071618A (ko) * 2016-12-20 2018-06-28 현대자동차주식회사 연료전지용 막전극 접합체 및 그 제조방법
WO2021132138A1 (fr) * 2019-12-23 2021-07-01 東レ株式会社 Procédé et appareil de production d'un ensemble membrane-électrode

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